Lifting device



M. Kok

LIFTING DEVICE Jan. 11, 1955 2 Sheets-Sheet 1 Filed Oct. 26, 1953 IN VENTOR AGENT M. KOK

LIF'TING DEVICE Jan. 1 1, 1955 2 Sheets-Sheet 2 Filed Oct. 26, 1953PIC-3.4

FIE-3.3

FIG.6

INVENTOR WWW/V0.5 49K BY 722cm ATTORNEY United States Patent Oflice.

2,699,354 Patented Jan. 11, 1955 LIFTIN G DEVICE Marinus Kok, De Steeg,Netherlands, assignor to N. V.

Betonfabriek De Meteoor, Rheden, Netherlands Application October 26,1953, Serial No. 388,228

Claims priority, application Netherlands November 19, 1952 4 Claims.(Cl. 294-96) The invention relates to improvements in a lifting device,especially for lifting heavy articles.

or lifting articles of great weight, e. g. large concrete rafts orslabs, it is known to provide the article with a nonround hole intowhich a lifting rod provided with a hammer-shaped head may be inserted,whereupon this rod is turned a quarter of a turn so that the head of therod engages the undersurface of the article to be lifted. Concrete raftsor slabs which are intended for composing a dock yard, a factory yard ora factory floor which must stand trafiic of very heavy vehicles would beweakened too much by a non-round hole.

The purpose of the invention is the provision of a lifting device whichis especially adapted to lift heavy concrete articles having acylindrical hole provided with a metal lining.

Another purpose of the present invention is the provision of a liftingdevice of such a kind that the cylindrical hole in the article to belifted can be kept as small as possible in order to weaken the articleto a minimum degree.

Still another purpose of the invention is the provision of a liftingdevice having pivotal spreading elements which engage the lower edge ofthe hole, e. g. the interior edge of the metal lining of the article tobe lifted in such a way that the pivots of the spreading elements do nottransmit the lifting force.

Still another purpose of the invention is the provision of a liftingdevice which is easily manufactured.

Still another purpose of the invention is the provision of a liftingdevice having spreading elements which are quickly and easily detachableif this is desired for cleaning or other purposes.

Still another purpose of the invention is the provision of a liftingdevice having spreading elements which can quickly and easily bereplaced by spreading elements of different dimensions if the liftingdevice is to be used for lifting articles having holes of a largerdiameter than the minimum diameter for which the device has beendesigned.

Still another purpose of the invention is the provision of a liftingdevice having an abutment intended to rest on the upper surface of thearticle to be lifted without needing to insert a tool between theabutment and the article if after releasing the lifting force, it isdesired to remove the lifting device from said article.

The characteristic features and the advantages of the lifting deviceaccording to the invention will follow from the subjoint description andthe claims appended thereto.

In order to elucidate the invention reference is made to theaccompanying drawings in which Fig. 1 is an elevation of a portion of aslab in which a lifting device according to the invention has beeninserted, said device being shown in the position before starting thelifting operation,

Fig. 2 is a vertical section of the object and of the lifting device inthe same position as Fig. 1,

Fig. 3 is a section of the lower portion of Fig. 2, however, with thedevice in the position before starting the lifting operation,

Fig. 4 is an elevation of a spreading element,

Fig. 5 is an elevation of the lower portion of an element of the liftingdevice shown in Fig. 2, but on a larger scale, and

Fig. 6 is a view of the resilient ring adapted to act as a fllllcrum forthe spreading elements, equally on a larger sca e.

De Steeg, Municipality With reference to the drawings a lifting bolt 1is screwed into a threaded yoke 2 and is locked in position by a locknot 3. The yoke 2 is welded at 4 to the legs of a U-shaped strap 5adapted to receive a lifting hook.

The object to be lifted, e. g. a concrete slab 6, has a hole providedwith a cylindrical lining 7, which is welded to reinforcing rods 8. Theupper face of the lining 7 is flush with the upper face of the concreteslab 6 while the lfower end of the lining is slightly higher than theunderace.

The lower end of the lifting rod 1 is provided with a conical head 9,the diameter of the larger end of which is such that said head can beinserted through the lining 7. A sleeve 10 provided with a horizontalflange 11 near its upper end, is axially movable with respect to thebolt 1 and has an exterior diameter which is a little smaller than theinterior diameter of the lining 7. The upper portion of the sleeve 10 isprovided with a handle consisting of a ring 12 and spokes 13, the latterbeing welded between said ring 12 and said flange 11.

Six radial slots 14 are formed in the lower end of the sleeve 10 whichserve as guides for the upper ends 15 of spreading elements 16. Theseelements are pivotally connected to the sleeve 10 by means of an openresilient wire ring 17 which engages a circumferential groove 18arranged in the slotted end of the sleeve 10, and recesses 19dfoir5nedin the spreading elements 16 below the upper en s If it is desired tolift a concrete slab 6, the lifting bolt 1 with the sleeve 10 and thespreading elements 16 which are pivotally connected thereto by thespring wire 17, is inserted into the lining 7 till the flange 11 of thesleeve 10 rests on the upper face of the slab 6. This position is shownin Fig. 2. Thereupon the strap 5 is hooked on the book of the liftingcable and the lifting rod is raised, while the sleeve 10 is held down bymeans of the handle 12. The elements 16 are spread by the conical head 9until these elements are clamped between the head 9 of the lifting bolt1 and the edge 20 of the lower end of the lining 7 (vide Fig. 3). Inthis way there is a. positive engagement between the head 9 of thelifting bolt 1 without the fulcrum about which the spreading elements 16are adapted to move and which is formed by the: spring wire 17, arestressed by the lifting force.

If it is desired after lifting the slab 6 and after lowering the sameagain until it rests on a support, to release the lifting device, thelifting bolt 1 is lowered until the elements associated therewith takeagain the position as shown in Fig. 2. The spreading elements 16 lieagain flat against the shank of the lifting bolt 1 so that by means ofthe handle 12 the sleeve 10 can be raised and thereupon the lifting boltis pulled from the lining 7 of the hole in the slab 6.

It follows from the above that the pivotal connection between the sleeve10 and the spreading elements 16 takes a minimum space so that theoverall diameter of the sleeve 10, the lifting bolt 1 with its head 9,the wire ring 17 and the spreading elements 16 is the smallestimaginable diameter for a lifting device with positive action of thespreading elements. This is of utmost importance if it is desired tokeep the hole in the article as small as possible.

The spring wire ring 17 rests in the bottom of the peripheral groove 18in the sleeve 10, so that the spreading elements 16 are not urgedagainstthe lifting rod 1. The upper ends 15 of the spreading elements 16form an angle with that portion of the spreading elements which is belowthe wire ring 17, which is equal to the angle between the shank of thelifting rod 1 and the conical head In this way the outward movement ofthe spreading elements 16 is allowed with a minimum clearance of theupper ends with respect to the lifting bolt 1.

The spring wire ring 17 has further the advantage that the assembly ofthe device is very easy. Further the spreading elements may easily bewithdrawn from the slots 14 since it is only necessary to widen the ring17 so far that it leaves the groove 18. This enables cleaning the devicein a very easy way, while it is also possible to substitute thespreading elements 16 by other spreading elements having an upperportion of the same shape as the portion 15, but a lower portion oflarger dimension in a radial sense, so that the device can be readilyadapted 2. A lifting device, comprising a lifting bolt having to liftarticles having a larger hole. v an enlarged lower end portion forming aunit with the It is remarked that the device described hereabove, shankof said bolt, a sleeve adapted to slide along said apart from liftingobjects, is also adapted for other purshank, a plurality of axial slotsin said sleeve engaging poses, e. g. for temporarily fixing a cable to ahorizontal 5 the upper portions of a plurality of spreading elements,sloping or vertical. surface of a block, provided that bean open ring ofspring wire forming a fulcrum which yond the end of'the hole there is acavity adapted to pivotally connects each of said spreading elements tothe receive the head of the lifting'rod. slotted portion of said sleeve.

Having described the invention and an embodiment 3. A lifting device,comprising a lifting bolt having an thereof, what is claimed is: 10integral conical head at its lower end, a sleeve adapted to 1. A liftingdevice, comprising a lifting bolt having an slide along said bolt, aplurality of axial slots in the lower enlarged lower end portion forminga unit with the shank end of said sleeve, a spreading element in each ofsaid oftsaid bolt, a sleeve adapted to move axially with reslots, afulcrum which pivotally. connects the upper porspect to said bolt, aplurality of axial slots in said sleeve tion of each spreading elementto the slotted portion of which are open at the lower end, acircumferential groove 15 the sleeve and a radial flange or similarabutment arin the slotted lower portion of said sleeve, a plurality ofranged on thenon-slotted portion of said sleeve. spreading elements theupper portion of which engage 4. A lifting device as claimed in claim 3,in which said said slots, recesses in the exterior faces of the upperporsleeve is provided with a handle at a higher level than said tions ofsaid spreading elements, and an open spring wire radial flange orsimilar abutment.

ring engaging said circumferential groove in the sleeve 20 and saidrecesses in the spreading elements. No references cited.

